A170940 4^n-2^n-2.
0, 10, 54, 238, 990, 4030, 16254, 65278, 261630, 1047550, 4192254, 16773118, 67100670, 268419070, 1073709054, 4294901758, 17179738110, 68719214590, 274877382654, 1099510579198, 4398044413950, 17592181850110, 70368735789054, 281474959933438, 1125899873288190
Offset: 1
Keywords
Examples
Contribution from _Omar E. Pol_, Mar 16 2010: (Start) n ...... a(n) written in base 2 ..... a(n) 1 ................ 0 ................ 0 2 ............... 1010 .............. 10 3 .............. 110110 ............. 54 4 ............. 11101110 ............ 238 5 ............ 1111011110 ........... 990 6 ........... 111110111110 .......... 4030 7 .......... 11111101111110 ......... 16254 8 ......... 1111111011111110 ........ 65278 9 ........ 111111110111111110 ....... 261630 10 ...... 11111111101111111110 ...... 1047550 (End)
Links
- Index entries for linear recurrences with constant coefficients, signature (7, -14, 8).
Crossrefs
Cf. A170926.
Formula
a(n)= 7*a(n-1) -14*a(n-2) +8*a(n-3) = 2*A129868(n-1). G.f.: 2*x^2*(-5+8*x)/((x-1) * (2*x-1) * (4*x-1)). [From R. J. Mathar, Feb 14 2010]
a(n) = 2*(A006516(n)-1) [From Omar E. Pol, Mar 16 2010]
Comments